Esju Small Cell RF Platform in a nutshell:
Esju’s Platform can be used in Medium Range and Local Area LTE/WCDMA base station products with a large data transfer capacity. The Platform’s maximum power is 2 W per antenna. The power can be scaled down, so the product can be tailored for the Local Area category. The number of antennas can also be specified for each individual customer.
The Platform is designed for quick, inexpensive creation of different frequency variants. Thus we are able to offer tested and proven solutions that can be quickly integrated into a final product according to the customer’s needs. Esju provides 3–6 months shorter time-to-market than a normal R&D project.
The Platform’s RF Front End is designed so that all the components are placed on one PCB. The figure below shows one transmitter-receiver pair. Any number of pairs can be duplicated according to the customer’s needs. We use a very dense component layout, so the resulting surface area is small. Variants of the front end can be made for the 1.5–2.7-Ghz frequency range simply by changing the assembly. This saves costly redesigning time.
Except for ceramic filters, all the components are inexpensive standard components supplied by known manufacturers. For outdoor use we have a mechanical structure cooled by natural convection, ensuring a very long operating time for the components.
Depending on the customer’s needs, lower- and higher-frequency versions of the platform’s RF front end can be made, the power can be changed, or it can incorporate indoor mechanics. The power amplifier can be linearized with both analog and digital predistortion. The figure below shows commercial analog predistortion-linearized signal.
The TRX part of the RF Platform is designed so that the same design fits all frequency variants with only small changes. This brings our customers significant cost savings, as just a little redesigning is needed for different variants and production logistics are simplified. The TRX part is implemented with only commercial components supplied by large manufacturers. The architecture includes one intermediate frequency, but if the customer wants to use integrated RF ASICs, for example, it can also be designed for a direct signal transformation.
The TRX-RF parts designed for two transmitter-receiver chains and their AD/DA converters take up only 140 mm x 50 mm of PCB surface. Two transmitter-receiver chains (2 x2 W), including the Front End, take up altogether only 140 mm x 190 mm, meaning the RF parts can be covered with an A5-size sheet of paper. The volume of this implementation is only about two liters.
Electromechanics Particular attention is focused on heat management and small size. Outdoor products can be manufactured inexpensively with die-casting. Indoor products can be made from sheet metal or cast plastic. The mechanics in the figure below can be used to construct a 2 x 2 W base station with a volume of only three liters.
Antennas are tailored according to the customer’s needs. Depending on the application, we can design either directional or circular polarizing antennas. The Platform also accepts ready antenna solutions.